Conventionally, an unmanned dump truck driving system is known as a system for transporting earth and sand by a dump truck for use, for instance in a quarrying site or the like of a large area. An example of an unmanned dump truck driving system is as described below. Teaching the traveling course to the unmanned dump truck is conducted by a specified method, and the coordinate data on the traveling course at each predetermined distance and each predetermined time are stored in a storage unit. At the time of automatic traveling, the unmanned dump truck confirms the current position where the dump truck is actually traveling at each predetermined sampling time, and computes the deviation between the actual position and the aforementioned traveling course data previously stored. Then, in order to reduce the deviation, the traveling control of steering, vehicle speed, start and halt of the unmanned dump truck is conducted, and the unmanned dump truck is controlled so as to run along the traveling course previously stored.
For example, Japanese Laid Open Patent Application No. 5-297942 discloses an unmanned dump truck driving system provided with an unmanned crawler dump truck, a loader, and a fixed station as shown in FIG. 26. Explaining the system based on FIG. 26, an unmanned crawler dump truck 91 and a fixed station 93 are respectively provided with bidirectional automatic tracking devices 94 and 95. The bidirectional automatic tracking devices 94 and 95 are automatically controlled by a control circuit section (not shown) so as to always receive light waves, which are sent to each other, on the front thereof. Thereby the distance and the direction of the unmanned crawler dump truck 91, with the fixed station 93 being set as a reference position, can be measured. Based on the measured results, a control device, not illustrated, in the fixed station 93 computes the current position of the unmanned crawler dump truck 91 as coordinate data in the driving system. The computed current position data are transmitted to the unmanned crawler dump truck 91 side by the medium of a data transmitter (not illustrated). Further, a loading position P1 at which the loader 92 loads the unmanned crawler dump truck 91 with earth and sand, or the like, and an unloading position P2 at which earth and sand, or the like loaded is discharged are provided in the driving system.
An automatic traveling course 96 for the unmanned crawler dump truck 91 to reciprocate between the loading position P1 and the unloading position P2 is obtained by teaching. The course data of the automatic traveling course 96 for which teaching is conducted are stored in the storage unit (not illustrated) of the unmanned crawler dump truck 91. When the unmanned crawler dump truck 91 conducts automatic traveling, the control device of the unmanned crawler dump truck 91 gives instructions to traveling control means (not illustrated) to control the steering, vehicle speed, start, and halt so as to reduce the deviation between the current position of the unmanned crawler dump truck 91 which is traveling and the course data in the aforementioned storage unit. In this way, the unmanned crawler dump truck 91 conducts automatic traveling along the automatic traveling course 96 between the loading position P1 and the unloading position P2, for which teaching has been conducted.
The teaching of the automatic traveling course 96 is conducted as described in the below. The operator of the dump truck gets into the driver's seat, and at first moves the crawler dump truck 91 to the loading position P1 to set the loading position P1 as a starting point. Thereafter, the automatic tracking devices 94 and 95 of the unmanned crawler dump truck 91 and the fixed station 93, are actuated, and each of them is automatically controlled so as to always receive the light waves, which both of the automatic tracking devices 94 and 95 send to each other, on the front thereof. The fixed station 93 computes the coordinate data of the current position of the unmanned crawler dump truck 91 at this time, and the current position data is transmitted to the unmanned crawler dump truck 91 side and stored in the storage unit.
Next, the operator operates the unmanned crawler dump truck 91 at a predetermined vehicle speed (for example, about 5 km/h) along the desired automatic traveling course 96. At this time, the control device of the unmanned crawler dump truck 91 conducts sampling at each predetermined interval (for example, 50 cm, or less) of the automatic traveling course 96, and the traveling coordinate data at each sampling point are stored in the storage unit in the unmanned crawler dump truck 91. The coordinate data is also stored at the unloading position P2 similarly to the above, and further the automatic traveling course 96 from the unloading position P2 up to the loading position P1 is also stored. After the teaching is completed, the unmanned crawler dump truck 91 conducts automatic traveling based on the course data in the storage unit.
However, in the aforementioned conventional teaching method, when a traveling course is changed, teaching has to be conducted again by operating the entire traveling course once again. For example, the change of the loading position P1 or the like is frequently required, therefore the change of the teaching has to be frequently conducted. In addition, strict positioning and vehicle attitude are required at the loading position P1 and the unloading position P2, therefore it is necessary to redo teaching many times under certain circumstances. Even in this case, teaching has to be redone by conducting teaching operation of the entire traveling course. Therefore, a great deal of time is spent on the change. In addition, the other dump trucks cannot operate while the change of teaching is made. Therefore, it is necessary to temporarily stop the operation of the unmanned vehicle driving system, thereby causing a disadvantage of reducing the availability of the unmanned vehicle driving system.
When conducting teaching of a simple reciprocating traveling course as in the aforementioned conventional method, the halt position at the time of conducting the teaching route is consistently considered as an earth discharging position, and earth can be discharged at this halt position at the time of automatic operation. However, when a plurality of dump trucks 3 run on the same automatic traveling course 96, standby is conducted to prevent interference with and collision against one another, or switching of moving forward [from/to] and/or reversing is conducted before the loading position P1 and the unloading position P2. Therefore, the traveling course becomes complicated. For this reason, it is necessary to conduct teaching of the functions (whether standby, switching moving forward [from/to] and/or reversing, discharging earth, and the like) at these halt positions in correspondence to the traveling course.